Recently, a device for determining the opening level of eyelid of eye which determines for example, whether an eyelid of the eye of the driver of the vehicle is opening or closing has been widely known.
For example, an eyelid opening level determining device disclosed in JP2004-192552A determines the opening level of the eyelid by combining an edge extraction process for detecting an edge line of an upper eyelid using a face image, a determining process for determining whether the eyelid is opening or closing according to a length of perpendicular line drawn from a peak point of an upper eyelid edge line to a line between both ends of the upper eyelid edge line, a determining process for determining whether the eyelid is opening or closing according to a vertical length of an eye binary image taken from the binaryzed face image, a determining process for determining whether the eyelid is opening or closing according to a distance between a peak point of the upper eyelid edge line and an eyebrow, and a determining process for determining whether the eyelid is opening or closing according to a curvature radius of the upper eyelid edge line.
When a part of a lower eyelid in the face image is lost due to overexposure, the distance between the peak point of the upper eyelid edge line and the lower eyelid cannot be detected correctly, thus the above mentioned eyelid opening level determination device cannot determine the eyelid opening level correctly. In addition, for determining the eyelid opening level based on the length of the perpendicular line drawn from the peak point of the upper eyelid edge line to a line between both ends of the upper eyelid edge line, when an inner corner of the eye or an outer corner of the eye is lacked, a line between the inner corner of the eye and the outer corner of the eye cannot be obtained correctly, thus the eyelid opening level determination device cannot determine the eyelid opening level correctly. In addition, for determining the eyelid opening level based on the distance between the peak point of the upper eyelid edge line and the eyebrow or curvature radius of the upper eyelid edge line, depending on the shape of the eyelid of the driver, the eyelid opening level determination device cannot determine the eyelid opening level correctly.
A need thus exists for an eyelid opening level determining device and a computer readable medium storing computer program thereof which is not susceptible to the drawback mentioned above.